Fuel Pressure

Mark Ruset · 01-30-2018, 09:07 PM

thanks to all who replied, I use a BG 280 with #12 line from the fuel cell to the pump #10 line to the regulator and #8 line from the regulator to the carb. My question was, does fuel pressure say set at 6 , 6 1/2 or 7 psi have any effect. And how much fuel pressure can the needle and seat withstand.

GTX JOHN · 01-31-2018, 01:27 AM

The higher the pressure goes the more strain on the needles and seats to do their job! I run 6 1/2 lbs. on my Quads and Thermo.
I have run 8 lbs. without a noticeable difference in performance if jetting is in the ballpark.......
But it triples my needle and seat issues!

jims5600 · 01-31-2018, 10:55 AM

Many years ago when I was racing,I found thru GM parts a needle and
seat that was used for motorhomes. We put that on a tow vehicle and
it cured some issues for us. Don't know if that is still available but it
would be something to think about.

nhramnl · 02-01-2018, 10:41 AM

Dean Oliver may respond on his own (if he sees this string), but he helped me overcome a problem I had with richness and smoke at idle and low speeds (e.g. driving around the pits). I checked and rechecked everything with my Q-Jet 305, including even fiddling around with various fuel pressure settings, and the problem would not go away. I called Dean and almost the first question he asked was "Which needle and seat is in the carb"? I told him it's the extra-super-big one that Edelbrock sells, and he told me to remove it and go to the next size smaller. His explanation was that there is so much fuel flow through the big Edelbrock needle and seat that the incoming fuel actually partially overcomes the ability of the needle to close completely, which functionally raises the float level and causes flooding. He also said that with any "normal" racing fuel pressure, the fuel enters the bowl so violently that it keeps the fuel in the bowl all "stirred-up". I changed to the smaller needle and seat and the condition is gone.

01-31-2018, 01:27 AM	#2
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,734 Likes: 2,803 Liked 2,487 Times in 698 Posts	Re: Fuel Pressure The higher the pressure goes the more strain on the needles and seats to do their job! I run 6 1/2 lbs. on my Quads and Thermo. I have run 8 lbs. without a noticeable difference in performance if jetting is in the ballpark....... But it triples my needle and seat issues! __________________ John Irving 741 Stock 741 Super Stock Last edited by GTX JOHN; 01-31-2018 at 01:29 AM.

01-31-2018, 10:55 AM	#3
jims5600 Member Join Date: Oct 2011 Posts: 125 Likes: 47 Liked 21 Times in 9 Posts	Re: Fuel Pressure Many years ago when I was racing,I found thru GM parts a needle and seat that was used for motorhomes. We put that on a tow vehicle and it cured some issues for us. Don't know if that is still available but it would be something to think about.

02-01-2018, 10:41 AM	#4
nhramnl Senior Member Join Date: Feb 2010 Posts: 507 Likes: 8 Liked 358 Times in 83 Posts	Re: Fuel Pressure Dean Oliver may respond on his own (if he sees this string), but he helped me overcome a problem I had with richness and smoke at idle and low speeds (e.g. driving around the pits). I checked and rechecked everything with my Q-Jet 305, including even fiddling around with various fuel pressure settings, and the problem would not go away. I called Dean and almost the first question he asked was "Which needle and seat is in the carb"? I told him it's the extra-super-big one that Edelbrock sells, and he told me to remove it and go to the next size smaller. His explanation was that there is so much fuel flow through the big Edelbrock needle and seat that the incoming fuel actually partially overcomes the ability of the needle to close completely, which functionally raises the float level and causes flooding. He also said that with any "normal" racing fuel pressure, the fuel enters the bowl so violently that it keeps the fuel in the bowl all "stirred-up". I changed to the smaller needle and seat and the condition is gone.

01-30-2018, 09:07 PM	#1
Mark Ruset Member Join Date: May 2006 Location: Southwest Florida Posts: 263 Likes: 35 Liked 43 Times in 29 Posts	Re: Fuel Pressure thanks to all who replied, I use a BG 280 with #12 line from the fuel cell to the pump #10 line to the regulator and #8 line from the regulator to the carb. My question was, does fuel pressure say set at 6 , 6 1/2 or 7 psi have any effect. And how much fuel pressure can the needle and seat withstand. __________________ Mark Ruset 2048 STK